Celebrating 40 years.
Quality Instrumentation for the Life Sciences

Effective May 1, 2022, PP Systems will no longer manufacture the CIRAS-3 SC and CIRAS-3 DC. We are evaluating the possibility of a replacement product in the future. We will, however, continue to support both the CIRAS-3 DC and CIRAS-3 SC products. If you have any questions or require additional information please do not hesitate to contact us.

CIRAS-3 DC CO2/H2O Gas Analyzer (Differential)

The CIRAS-3 DC is a lightweight, robust instrument with a rugged aluminum and polyurethane enclosure making it an ideal instrument for both field and lab.  It uses the same high performance, differential CO2 and H2O gas analyzer used in our popular CIRAS-3 Portable Photosynthesis System designed for high level leaf gas exchange research.  Our innovative “Auto Zero” measurement principle ensures long term stability and accuracy of both CO2 and H2O which is a significant advantage over “gas switching” systems.  The gas analyzers include an infrared source, highly polished and gold plated sample cells and specially selected detectors optimized for CO2 and H2O.  The optical bench is temperature controlled and pressure compensated ensuring the most accurate CO2 and H2O measurements under changing ambient conditions.


  • Photosynthesis and respiration
  • Plant physiology
  • Soil CO2 efflux
  • Whole canopy assimilation
  • Homemade chambers
  • Global change & atmospheric studies
  • FACE studies
  • Forest & agricultural meteorology
  • Air-sea surface exchange (pCO2)

 Powerful Software

Simple, intuitive and menu-driven software is designed into the system for system setup, operation, recording and data management.  On-line help is available throughout the software to guide you every step of the way.

Numeric Display

Remote Display_Numeric_DC


Graphical Display

Remote Display_Graphic_DC

Users can customize the presentation of data in the graphical display.  You can display up to 5 parameters and up to 3 graphs simultaneously on one display.

Gas sampling inlet and outlet ports for direct connection to the gas analyzers

Convenient, pluggable terminal block for analog signals

Product Features

  • High precision instrument featuring 4 independent, non-dispersive infrared gas analyzer for both CO2 and H2O (True Differential Analyzer)
  • CO2 measurement range: Up to 10000 umol mol-1
  • H2O measurement range: 0-75 mb
  • Fast response and long term stability with built-in Auto Zero
  • Fully compensated for changes in temperature, pressure and foreign gas broadening
  • Large, full color 7″ transflective LCD with optimized viewing angle (30 o)
  • Large numeric and graphical presentation of data
  • Unlimited data storage (internal memory and USB flash drive)
  • Analog and digital (USB) output
  • Built-in  sampling pumps with mass flow controllers for reference and analysis
  • Powerful, intuitive user interface and software
  • On-line Help
  • Remote display capability
  • Internal 7.2V Li-Ion rechargeable battery (optional) for portability
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